Product Specs

Table Of Contents
29 CCM AES CCM mode encryption
Page
272
Property Address offset Description
Important: MIC is not added to empty packets
29.8 EasyDMA and ERROR event
The CCM implements an EasyDMA mechanism for reading and writing to the RAM.
In some scenarios where the CPU and other DMA enabled peripherals are accessing the RAM at the same
time, the CCM DMA could experience some bus conflicts which may also result in an error during encryption.
If this happens, the ERROR event will be generated.
The EasyDMA will have finished accessing the RAM when the ENDKSGEN and ENDCRYPT events are
generated.
If the CNFPTR, SCRATCHPTR, INPTR and the OUTPTR are not pointing to the Data RAM region,
an EasyDMA transfer may result in a HardFault or RAM corruption. See Memory on page 23 for more
information about the different memory regions.
29.9 Registers
Table 60: Instances
Base address
Peripheral
Instance
Description
Configuration
0x4000F000
CCM
CCM
AES CCM Mode Encryption
Table 61: Register Overview
Register
Offset
Description
TASKS_KSGEN
0x000
Start generation of key-stream. This operation will stop by itself when completed.
TASKS_CRYPT
0x004
Start encryption/decryption. This operation will stop by itself when completed.
TASKS_STOP
0x008
Stop encryption/decryption
EVENTS_ENDKSGEN
0x100
Key-stream generation complete
EVENTS_ENDCRYPT
0x104
Encrypt/decrypt complete
EVENTS_ERROR
0x108
CCM error event
SHORTS
0x200
Shortcut register
INTENSET
0x304
Enable interrupt
INTENCLR
0x308
Disable interrupt
MICSTATUS
0x400
MIC check result
ENABLE
0x500
Enable
MODE
0x504
Operation mode
CNFPTR
0x508
Pointer to data structure holding AES key and NONCE vector
INPTR
0x50C
Input pointer
OUTPTR
0x510
Output pointer
SCRATCHPTR
0x514
Pointer to data area used for temporary storage
29.9.1 SHORTS
Address offset: 0x200
Shortcut register
Bit number
Id
Reset 0x00000000
31 30
0 0
29
0
28
0
27
0
26
0
25
0
24
0
23 22 21 20
0 0 0 0
19
0
18
0
17
0
16
0
15
0
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
A
0
Id RW Field
Value Id
Value
Description
A RW ENDKSGEN_CRYPT
Shortcut between ENDKSGEN event and CRYPT task
See EVENTS_ENDKSGEN and TASKS_CRYPT
Disabled
0
Disable shortcut
Enabled
1
Enable shortcut